An efficient chatter cutting method for difficult-to-machine materials

Abstract

The present invention discloses an efficient chatter cutting method for difficult-to-machine materials, which relates to the technical field of cutting processing and includes the following contents: Install the chatter tool shank on the machine tool, start the machine tool, and generate self-excited chatter by using the cutting energy of the tool system itself to perform chatter cutting; During the chatter cutting process, the chatter tool shank is excited to generate stable vibration, and the tool forms a ratchet-shaped motion trajectory. The ratchet-shaped motion trajectory includes the process of the tool extruding the workpiece surface and the process of the tool separating from the workpiece surface, and a ratchet-shaped surface topography is formed on the workpiece surface; During the process of the tool separating from the workpiece surface, cutting fluid is allowed to enter the separated cutting area for cooling and lubrication to reduce the cutting temperature. In the present invention, the tool forms a ratchet-shaped motion trajectory, periodically extrudes and separates from the workpiece surface, and uses cutting fluid to cool and lubricate the separated cutting area when separating from the workpiece surface, thereby forming a ratchet-shaped surface topography on the workpiece surface, which can reduce the cutting temperature, reduce tool wear, and improve processing efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of cutting processing, and in particular to a flutter cutting method for difficult-to-process materials. Background Art

[0002] Ultrasonic vibration cutting technology is a forced excitation cutting method that applies high-frequency micron-level amplitude to the blade through an external power supply and transducer. It has the advantages of reducing cutting force, reducing cutting temperature, increasing tool life, and improving the integrity of the processed surface, and has gradually become an advanced precision machining method. However, due to its low excitation power, small vibration amplitude, complex structure and high cost, it is limited in its wide application.

[0003] Self-excited vibration cutting technology is a self-excited vibration cutting method that relies on the cutting energy of the tool system to generate an amplitude of tens of microns. It has the advantages of simple structure, high excitation power, and large vibration amplitude. It has been applied in the fields of efficient vibration turning to generate metal short fibers, efficient vibration chip breaking and deep hole drilling, and efficient vibration rough grinding to reduce burns. However, there has been no attention paid to the tool life of vibration cutting and its impact on processing efficiency. Instead, the main focus has been on how to suppress the generation of vibration in processing situations.

[0004] As the performance requirements of aerospace equipment continue to increase, high-temperature alloys and titanium alloys are widely used. However, they have high cutting forces, high cutting temperatures, fast tool wear, low processing efficiency, and poor machinability, making them recognized as difficult-to-process materials. In particular, the processing allowance of difficult-to-process material components is large, accounting for the majority of the total processing time. Therefore, how to improve the processing efficiency of difficult-to-process materials is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a vibration cutting method for difficult-to-process materials to solve the problems existing in the above-mentioned prior art. During the vibration cutting process, the vibration tool rod is excited to vibrate stably, and the tool forms a ratchet-type motion trajectory, which can periodically squeeze and detach from the workpiece surface. When detaching from the workpiece surface, the cutting fluid is used to cool and lubricate the separation cutting area, thereby forming a ratchet-type surface morphology on the workpiece surface, which can reduce the cutting temperature, reduce tool wear, and improve processing efficiency.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a flutter cutting method for difficult-to-machine materials, comprising the following contents:

[0008] Install the chatter tool bar on the machine tool, turn on the machine tool, and use the cutting energy of the tool system to generate self-excited chatter to perform chatter cutting;

[0009] During the chatter cutting process, the chatter tool bar is excited to produce a stable vibration, and the tool forms a ratchet-shaped motion trajectory, which includes a process in which the tool squeezes the workpiece surface and the tool separates from the workpiece surface, forming a ratchet-shaped surface morphology on the workpiece surface;

[0010] During the process of separation of the tool from the workpiece surface, the cutting fluid enters the separation cutting zone for cooling and lubrication to reduce the cutting temperature.

[0011] Preferably, the process within one vibration cycle of the ratchet-type motion trajectory includes: the cutting depth gradually increases, the dynamic back angle continuously decreases until a negative back angle appears, the back tool face continuously squeezes the workpiece surface, the cutting force increases, and the cutting heat accumulates; the tool back angle gradually increases, the cutting depth first increases and then decreases, the cutting force first increases and then decreases, the contact area between the back tool face and the workpiece first increases and then rapidly decreases, the tool back tool face gradually separates from the workpiece surface, the cutting fluid is sprayed from the back tool face of the blade into the separation cutting area, and the cutting temperature drops rapidly.

[0012] Preferably, the vibrating tool bar is designed and manufactured according to the selected processing materials and cutting parameters to ensure that the vibration parameters of the vibrating tool bar are within a reasonable vibration parameter range; the processing materials include aluminum / magnesium / copper alloys, stainless steel, titanium alloys, high-temperature alloys, high-strength steels and composite materials; the cutting parameters include cutting line speed, cutting depth and feed rate; the vibration parameters include the main amplitude and main frequency in the main vibration direction of the vibrating tool; the reasonable vibration parameter range is related to the workpiece material, tool material and cutting amount, and is based on extending the tool life compared to ordinary cutting.

[0013] Preferably, the vibration tool bar needs to have its rigidity weakened, and the direction of the rigidity weakening is perpendicular to the direction of the machining surface or along the direction of the rotary cutting speed. During the cutting process, the dynamic change of the cutting force stimulates the vibration tool bar to vibrate along the direction of weak rigidity. At the same time, the rigidity cannot be too weak, so as to extend the tool life compared to ordinary cutting.

[0014] Preferably, the stiffness control method includes changing the tool bar material, selecting materials with different elastic moduli as the tool bar material according to needs, and also includes changing the tool bar shape or structure to extend the tool life compared to ordinary cutting.

[0015] Preferably, the ratchet-shaped surface topography is generated by vibration in one or more directions, and the trajectory equation of the relative motion between the tool and the workpiece is as follows:

[0016] X=A 2 sin(ωt)

[0017] Y=A 1 sin(ωt+φ)+vt

[0018] Where X is the displacement perpendicular to the workpiece surface, Y is the displacement along the cutting speed direction, and A 1 is the amplitude along the cutting speed direction, and A 2 is the amplitude perpendicular to the workpiece surface, ω is the chatter frequency of the tool in the cutting speed direction, φ is the phase difference between the vibrations in the two directions, t is time, v is the cutting linear speed. Taking Y as the abscissa and X as the ordinate, the relative motion trajectory of the tool and the workpiece can be obtained.

[0019] Preferably, a three-axis acceleration sensor is attached to the vibrating part of the chatter tool shank to measure the amplitudes, frequencies, and phase differences in each direction, determine the vibration trajectories of the chatter tool shank and the tool. The main chatter frequency of the chatter tool shank is close to the natural frequency in the main vibration direction. Perform natural modal analysis and design on the chatter tool shank to control the chatter frequency.

[0020] Preferably, the chatter cutting includes chatter turning, chatter milling, chatter grinding, chatter drilling, chatter reaming, and chatter counterboring.

[0021] Preferably, the cutting fluid is oil-based cutting fluid, oil-based cutting mist, water-based cutting fluid, water-based cutting mist, or liquid nitrogen, and the cutting fluid pressure is determined according to the machine tool conditions and process effect requirements.

[0022] Preferably, the machine tool includes a lathe, a milling machine, a drill press, a grinding machine, and a machining center capable of performing cutting processing operations.

[0023] The present invention has achieved the following technical effects compared with the prior art:

[0024] During the chatter cutting process of the present invention, the chatter tool shank is excited to generate stable vibrations, and the tool forms a ratchet-shaped motion trajectory, which can periodically squeeze and disengage from the workpiece surface. When disengaging from the workpiece surface, the cutting fluid is used to cool and lubricate the separated cutting area, thereby forming a ratchet-shaped surface topography on the workpiece surface. Control the chatter of the chatter tool shank within a reasonable vibration parameter range. For the chatter cutting of difficult-to-machine materials, the tool life can be significantly extended compared to ordinary cutting, thereby improving the processing efficiency. At the same time, the chatter tool shank has a simple structure, convenient application, and low price. Therefore, chatter cutting can become an advanced method for the high-efficiency machining of difficult-to-machine materials.

[0025] In addition, the present invention can also achieve the following technical effects:

[0026] The present invention effectively controls and utilizes the chatter that is generally considered harmful to the machining process, obtains inspiration from the sound production process of male katydids, separates and contacts periodically, enables the scraping teeth to have excellent wear resistance, extends the tool life through reasonable chatter cutting, and improves the processing efficiency.

[0027] The present invention can design and manufacture a reasonable chatter tool shank according to the machining parameters of different difficult-to-machine materials, and utilize the cutting energy of the tool system itself to generate self-excited chatter with an amplitude of dozens of micrometers. Compared with the traditional vibration cutting tool shank structure, it is simple in structure, convenient to manufacture, does not require an external excitation power supply, and has a lower cost.

[0028] The chatter cutting method of the present invention can be applied to a variety of cutting processes, such as turning, milling, drilling, reaming, grinding, and countersinking, etc., to achieve the efficient machining of difficult-to-machine materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is the morphology of the file and plectrum of the katydid;

[0031] Figure 2 It is the schematic diagram of two-direction vibration;

[0032] Figure 3 It is the schematic diagram of the chatter cutting method;

[0033] Figure 4 It is the physical diagram of the machined surface morphology of chatter cutting;

[0034] Figure 5 It is the structural diagram of the turning chatter tool shank;

[0035] Figure 6 It is the schematic diagram of the vibration measurement system;

[0036] Figure 7 It is the comparison diagram of the three-axis amplitude measurement results;

[0037] Figure 8 It is the measurement diagram of the change of chatter frequency during the chatter cutting process;

[0038] Figure 9 It is the schematic diagram of the chatter turning outer circle;

[0039] Figure 10 It is the schematic diagram of the chatter turning end face;

[0040] Figure 11 It is the schematic diagram of the chatter turning inner hole;

[0041] Figure 12 It is the vibration measurement of the tool shank with a cutting linear speed of 30 m / min;

[0042] Figure 13Vibration measurement of the tool bar at a cutting linear speed of 40 m / min;

[0043] Figure 14 Vibration measurement of the tool bar at a cutting linear speed of 45 m / min;

[0044] Figure 15 Vibration measurement of the tool bar at a cutting linear speed of 50 m / min;

[0045] Figure 16 Vibration measurement of the tool bar at a cutting linear speed of 60 m / min;

[0046] Figure 17 Comparison diagram of tool wear between chatter cutting and ordinary cutting at a speed of 30 m / min;

[0047] Figure 18 Comparison diagram of tool wear between chatter cutting and ordinary cutting at a speed of 40 m / min;

[0048] Figure 19 Comparison diagram of tool wear between chatter cutting and ordinary cutting at a speed of 45 m / min;

[0049] Figure 20 Comparison diagram of tool wear between chatter cutting and ordinary cutting at a speed of 50 m / min;

[0050] Figure 21 Comparison diagram of tool wear between chatter cutting and ordinary cutting at a speed of 60 m / min;

[0051] Figure 22 Comparison diagram of surface roughness between chatter cutting and ordinary cutting at a speed of 30 m / min;

[0052] Figure 23 Comparison diagram of surface roughness between chatter cutting and ordinary cutting at a speed of 40 m / min;

[0053] Figure 24 Comparison diagram of surface roughness between chatter cutting and ordinary cutting at a speed of 45 m / min;

[0054] Figure 25 Schematic diagram of the side of chatter milling;

[0055] Figure 26 Schematic diagram of the rounded corner of chatter plunge milling;

[0056] Figure 27 Schematic diagram of chatter grinding;

[0057] Figure 28 Schematic diagram of chatter drilling;

[0058] Figure 29 Schematic diagram of chatter reaming;

[0059] Figure 30 Schematic diagram of chatter counterboring

[0060] Among them, 1, clamping part; 2, overhanging part; 3, mounting surface; 4, tool slot; 5, threaded hole; 6, blade; 7, workpiece; 8, milling cutter; 9, grinding head; 10, drill bit; 11, reamer rod; 12, counterboring drill Specific implementation manner

[0061] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention

[0062] The purpose of the present invention is to provide a chatter cutting method for difficult-to-machine materials to solve the problems existing in the prior art. During the chatter cutting process, a stable vibration is excited in the chatter tool bar, and the tool forms a ratchet-shaped motion trajectory, which can periodically squeeze and disengage from the surface of the workpiece. When disengaging from the surface of the workpiece, cutting fluid is used to cool and lubricate the separated cutting area, so as to form a ratchet-shaped surface topography on the surface of the workpiece, which can reduce the cutting temperature, reduce tool wear, and improve the machining efficiency

[0063] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners

[0064] The present application is proposed based on the bionic inspiration of katydids: Katydids refer to a kind of Tettigoniidae, commonly known as katydids. The wings of male katydids are left-overlapping wings, that is, the left wing covers the right wing. The shapes of the left wing and the right wing are quite different. As Figure 1 shown, the dark area on the ventral surface of the left wing is a ridge-like band called the file, and there is a tissue similar to the wing vein on the back edge of the right wing called the plectrum. When the plectrum moves on the file and rubs against the file, it makes a chirping sound. Each tooth on the file is not symmetrical on both sides. One side is gentle and the other side is steep. The moving direction of the plectrum is opposite to the deflection direction of the tooth, which can be called reverse ratchet teeth. The plectrum scraping on the reverse ratchet teeth generates stable self-excited vibration (referred to as chatter in machining), also known as scraping vibration. The periodic separation of the plectrum and the reverse ratchet teeth in the scraping vibration effectively reduces the friction force and frictional heat during the scraping process, greatly reducing the wear of the plectrum and the reverse ratchet teeth. Therefore, male katydids can rub their wings 50 million - 60 million times throughout the summer

[0065] Based on the friction reduction effect during the scraping vibration process of the plectrum and file on the katydid wing, the present invention conducts feature extraction and simplification, and proposes a chatter cutting method for difficult-to-machine materials. This method equivalentizes the chatter tool shank and tool to a plectrum, excites stable chatter, obtains a workpiece surface topography in the shape of reverse ratchet teeth. At the same time, the periodic separation of the flank face of the tool and the workpiece surface enables the cutting fluid to enter the cutting area, greatly reducing tool wear, extending tool life, and improving machining efficiency.

[0066] Specifically, as Figures 2 to 30 shown, the present invention provides a chatter cutting method for difficult-to-machine materials, including the following content:

[0067] Install the chatter tool shank on the machine tool, start the machine tool, and use the cutting energy of the tool system itself to generate self-excited chatter for chatter cutting. The chatter tool shank mentioned here can be divided into turning tool shanks, milling tool shanks, drilling tool shanks, etc. according to different cutting methods, and different forms of tools are installed on the chatter tool shank;

[0068] During the chatter cutting process, the chatter tool shank is excited to generate stable vibrations, and the tool forms a ratchet-shaped motion trajectory. It should be noted that: reasonable chatter tool shanks can be designed and manufactured according to the processing parameters of different difficult-to-machine materials, and self-excited chatter with an amplitude of dozens of micrometers can be generated using the cutting energy of the tool system itself. Compared with the traditional vibration cutting tool shank structure, it is simple in structure, convenient to manufacture, does not require an external excitation power supply, and has a lower cost. The formed ratchet-shaped motion trajectory includes the process of the tool squeezing the surface of workpiece 7 and the tool detaching from the surface of workpiece 7, forming a ratchet-shaped surface topography on the surface of workpiece 7;

[0069] During the process of the tool separating from the surface of workpiece 7, the cutting fluid can be controlled to spray towards the cutting area under a certain pressure, so that the cutting fluid enters the separated cutting area for cooling and lubrication, thereby reducing the cutting temperature.

[0070] In the present invention, during the chatter cutting process, the chatter tool shank is excited to generate stable vibrations, the tool forms a ratchet-shaped motion trajectory, can periodically squeeze and detach from the surface of workpiece 7, and uses the cutting fluid to cool and lubricate the separated cutting area when detaching from the surface of workpiece 7, thereby forming a ratchet-shaped surface topography on the surface of workpiece 7. Controlling the chatter of the chatter tool shank within a reasonable vibration parameter range can greatly extend the tool life for the chatter cutting of difficult-to-machine materials compared with ordinary cutting, and thus improve the machining efficiency. At the same time, the chatter tool shank has a simple structure, convenient application, and low price. Therefore, chatter cutting can become an advanced method for the high-efficiency machining of difficult-to-machine materials.

[0071] As Figure 3 and Figure 4As shown, the chatter cutting process has a large feed and depth of cut. It is a continuous cutting process and is different from the interrupted cutting process of ultrasonic machining. The generation of chatter causes the relative speed, depth of cut, and tool angle between the tool and the workpiece 7 to continuously change during the machining process. As Figure 3 shown, within one vibration cycle of the envelope curve of the tooth-shaped motion trajectory at the tool tip, the cutting tool moves from point P1 to P2, the depth of cut gradually increases, the dynamic clearance angle continuously decreases until a negative clearance angle appears, and the flank continuously presses against the surface of the workpiece 7, as shown in the shaded area in the figure. The cutting force increases and the cutting heat accumulates; P2 is the minimum value of the clearance angle; when the cutting tool moves from P2 to P3, the clearance angle gradually increases, the depth of cut first increases and then decreases, the cutting force first increases and then decreases, the contact area between the flank and the workpiece 7 first increases and then rapidly decreases, the flank of the tool gradually separates from the surface of the workpiece 7, the cutting fluid begins to enter the flank area for cooling and lubrication, and the cutting temperature rapidly drops, forming a Figure 4 tooth-shaped surface topography as shown. This is also the reason why the periodic separation of the flank during reasonable chatter cutting can significantly improve the tool life. During the entire chatter cutting process, as the vibration repeats periodically, the above process also appears periodically. It should be noted that when the amplitude of the main vibration direction is too large, the acceleration of the tool also increases, the interference of the flank extrusion increases, and the impact load borne during the cutting process is too large, resulting in a sharp reduction in the tool life. Therefore, a reasonable amplitude of the main vibration is crucial for extending the tool life.

[0072] The chatter tool shank needs to be designed and manufactured according to the selected machining material and cutting parameters to ensure that the vibration parameters of the chatter tool shank are within the reasonable vibration parameter range. Among them, the machining material can be aluminum / magnesium / copper alloy, stainless steel, titanium alloy, superalloy, high-strength steel, and composite materials, etc.; the cutting parameters include cutting linear speed, depth of cut, and feed rate; the vibration parameters include the main amplitude and main frequency of the main vibration direction of chatter; the reasonable vibration parameter range is related to the workpiece material, tool material, and cutting amount, and is based on being able to extend the tool life compared with ordinary cutting.

[0073] On the one hand, during the design and manufacturing process of the chatter tool shank, for the selected machining material and cutting parameters, in order to be able to excite the stable vibration of the chatter tool shank during the cutting process, the stiffness of the chatter tool shank needs to be weakened. The direction of stiffness weakening is perpendicular to the machining surface direction or along the rotary cutting speed direction, so that during the cutting process, the dynamic change of the cutting force can excite the chatter tool shank to chatter along the weak stiffness direction; on the other hand, to ensure the stable chatter of the chatter tool shank and prevent the chatter from getting out of control and the amplitude from being too large, the stiffness cannot be too weak. Therefore, the key to the design and manufacturing of the chatter tool shank is the control of stiffness.

[0074] The methods for stiffness control include: ① changing the tool shank material and selecting materials with different elastic moduli as the tool shank material according to needs; ② changing the tool shank shape or structure.

[0075] AsFigure 2 As shown, the surface topography of the ratchet type is generated by vibration in one or more directions. The trajectory equation of the relative movement between the tool and the workpiece 7 is as follows:

[0076] X = A 2 sin(ωt)

[0077] Y = A 1 sin(ωt + φ) + vt

[0078] In the formula, X is the displacement perpendicular to the surface of the workpiece 7, Y is the displacement along the cutting speed direction, A 1 is the amplitude along the cutting speed direction, A 2 is the amplitude perpendicular to the surface of the workpiece 7, ω is the chatter frequency of the tool in the cutting speed direction, φ is the phase difference between the vibrations in two directions, t is time, and v is the cutting linear speed. Taking Y as the abscissa and X as the ordinate, the trajectory of the relative movement between the tool and the workpiece 7 can be obtained.

[0079] During the chatter cutting process, the amplitudes, frequencies, and phase differences in each direction can be measured. When measuring, a three-axis acceleration sensor can be attached to the vibrating part of the chatter tool bar for measurement. According to the measurement results, the vibration trajectory of the chatter tool bar and the tool can be determined. The main chatter frequency of the chatter tool bar is close to the natural frequency in the main vibration direction (the direction with the largest amplitude). By performing natural modal analysis and design on the chatter tool bar, the chatter frequency can be regulated.

[0080] When using different chatter tool bars for chatter cutting, various cutting processing technologies can be formed. For example: combined with turning, there can be a chatter turning method; combined with milling, there can be a chatter milling method; combined with grinding, there can be a chatter grinding method; combined with drilling, there can be an axial chatter drilling method; combined with reaming, there can be a chatter reaming method; combined with countersinking, there can be a chatter countersinking method.

[0081] The cutting fluid can be oil-based cutting fluid, oil-based cutting mist, water-based cutting fluid, water-based cutting mist, or liquid nitrogen, etc. The cutting fluid pressure is determined according to the machine tool conditions and process effect requirements.

[0082] The machine tool refers to lathes, milling machines, drilling machines, grinding machines, machining centers, etc. that can perform various cutting processing technologies.

[0083] According to the solutions described above, the present invention provides multiple specific embodiments.

[0084] Embodiment 1: Chatter turning of GH4169 superalloy

[0085] S1: The workpiece 7 is fixed on the lathe, and the cutting parameters are selected (the cutting linear speed of the tool is 30 m / min, the cutting depth is 0.2 mm, and the feed rate is 0.1 mm / r). A turning chatter tool bar matching the selected cutting parameters is designed and manufactured. Taking turning as an example, the shape of the tool bar is as Figure 5 shown. The chatter tool bar is processed with weak rigidity. The material is selected as aluminum alloy 6061. The tool bar structure is divided into a clamping part 1 and an overhanging part 2. The clamping part 1 is in the shape of a cuboid, and the overhanging part 2 is in the shape of a cylinder. The cross-sectional diameter of the overhanging part 2 is 30 mm. The front end of the overhanging part 2 is an installation surface 3 for installing the blade 6. The installation surface 3 coincides with the central plane of the cylindrical overhanging part 2 and is parallel to the top or bottom surface of the clamping part 1. At the center of the front end of the installation surface 3, there is a tool groove 4 for installing the blade 6. The width of the installation surface 3 is 13 mm. At the bottom of the tool groove 4, there is a threaded hole 5 for fixing the blade 6. The specification of the threaded hole 5 is M4. The chatter tool bar is clamped on the tool holder. The bottom surface of the clamping part 1 contacts the bottom surface of the tool holder, and the top surface is clamped by a tool holder screw. The most important dimension of the chatter tool bar is the length of the overhanging part 2. Changing the length of the overhanging part 2 can adjust the modal parameters of the chatter tool bar, and further control the vibration parameters such as the amplitude and frequency of the tool bar during the machining process. As Figure 6 shown in the vibration measurement system, the chatter tool bar is clamped on the turning tool holder. The triaxial acceleration sensor is fixed on the bottom surface of the front end of the overhanging part 2, and the amplitudes of the chatter tool bar in three directions are measured simultaneously. The measurement results are as Figure 7 shown. It is found that during the whole machining process when the flank wear of the tool reaches VBmax = 0.3 mm, the vibration amplitude of the tool bar is stable. The vibration is mainly divided into the cutting speed direction and the cutting depth direction. The vibration amplitude in the feed direction is very small and can be ignored. At the same time, the chatter frequency is also relatively stable. As Figure 8 shown, the chatter frequency of the tool bar in the cutting speed direction is close to the natural frequency of the first-order bending vibration of the tool bar, and the vibration phase difference between the two directions is 0°. Therefore, the vibration trajectories of the blade 6 when turning the workpiece 7 in three turning methods are as Figures 9 to 11 shown. The turning methods include external turning, face turning, and internal hole turning. The cutting parameters are selected (the cutting linear speed of the tool is 30 m / min, the cutting depth is 0.2 mm, and the feed rate is 0.1 mm / r). A matching turning chatter tool bar is designed and manufactured for the selected cutting parameters. When using a turning tool to turn the external circle of the workpiece, as Figure 12 shown in the measurement results, the vibration directions of the tool bar and the tool excited are divided into the cutting speed direction and the radial cutting depth direction. The main vibration frequency is 5000 Hz, the amplitude of the main vibration direction is 12 - 13 μm, and the vibration phase difference between the two directions is 0°. The cutting parameters are selected (the cutting linear speed of the tool is 40 m / min, the cutting depth is 0.2 mm, and the feed rate is 0.1 mm / r). A matching turning chatter tool bar is designed and manufactured for the selected cutting parameters. When using a turning tool to turn the external circle of the workpiece, as Figure 13The measured results show that the vibration directions of the tool shank and the tool are along the cutting speed direction and the radial depth of cut direction. The main vibration frequency is 5000 Hz, the amplitude of the main vibration direction is 14 - 16 μm, and the vibration phase difference between the two directions is 0°. The cutting parameters are selected (the cutting linear speed of the tool is 45 m / min, the depth of cut is 0.2 mm, and the feed rate is 0.1 mm / r). A turning chatter tool shank is designed and manufactured to match the selected cutting parameters. When turning the outer circle of the workpiece with a turning tool, as Figure 14 The measured results show that the vibration directions of the tool shank and the tool are along the cutting speed direction and the radial depth of cut direction. The main vibration frequency is 5000 Hz, the main vibration amplitude is 15 - 16 μm, and the vibration phase difference between the two directions is 0°. The cutting parameters are selected (the cutting linear speed of the tool is 50 m / min, the depth of cut is 0.2 mm, and the feed rate is 0.1 mm / r). A turning chatter tool shank is designed and manufactured to match the selected cutting parameters. When turning the outer circle of the workpiece with a turning tool, as Figure 15 The measured results show that the vibration directions of the tool shank and the tool are along the cutting speed direction and the radial depth of cut direction. The main vibration frequency is 5000 Hz, the main vibration amplitude is 16 - 18 μm, and the vibration phase difference between the two directions is 0°. The cutting parameters are selected (the cutting linear speed of the tool is 60 m / min, the depth of cut is 0.2 mm, and the feed rate is 0.1 mm / r). A turning chatter tool shank is designed and manufactured to match the selected cutting parameters. When turning the outer circle of the workpiece with a turning tool, as Figure 16 The measured results show that the vibration directions of the tool shank and the tool are along the cutting speed direction and the radial depth of cut direction. The main vibration frequency is 5800 Hz, the main vibration amplitude is 10 - 12 μm, and the vibration phase difference between the two directions is 0°.

[0086] S2: Set the cutting fluid pressure to 5 bar, turn on the cutting fluid supply, and spray it onto the flank separation area of the chatter cutting.

[0087] S3: Install the turning chatter tool shank on the corresponding machine tool, turn on the machine tool, and perform chatter cutting.

[0088] The flank face of the turning tool is periodically separated from the surface of the workpiece 7, and the cutting fluid flows into the cutting core area for cooling. Under the cutting parameters of a speed of 30 m / min, 40 m / min, and 50 m / min, a feed rate of 0.1 mm / r, and a cutting depth of 0.2 mm, the tool life of chatter cutting is 3 times that of ordinary cutting; under the cutting parameters of a speed of 45 m / min, a feed rate of 0.1 mm / r, and a cutting depth of 0.2 mm, the tool life of chatter cutting is 5 times that of ordinary cutting; while under the cutting parameters of a speed of 60 m / min, a feed rate of 0.1 mm / r, and a cutting depth of 0.2 mm, although the main vibration parameters of the tool shank are within a reasonable range at this time, the tool life of chatter cutting is only increased by 20% compared with ordinary cutting. This is because the cutting speed is relatively high at this time, the cutting heat accumulates quickly, and the cooling effect of the flank face separation is greatly weakened. The life curves at speeds of 30, 40, 45, 50, and 60 m / min are respectively as Figure 17 , 18 , 19, 20, and 21 show. At the same time, the surface quality of chatter cutting does not deteriorate significantly, and the surface roughness is slightly greater than that of ordinary cutting, within a reasonable range, as Figure 22 , 23 , and 24 show. This shows that under these process conditions, an amplitude of 10 - 30 μm can effectively extend the tool life and maintain a better surface roughness value below Ra1.6.

[0089] Example 2: Chatter Milling of GH4169 Superalloy

[0090] S1: The workpiece 7 is fixed on the milling machine, and the cutting parameters are selected (the cutting linear speed of the tool is 50 m / min, the radial cutting depth is 0.2 mm, the axial cutting depth is 8 mm, and the feed rate is 0.1 mm / r). A milling chatter tool shank is designed and manufactured to match the selected cutting parameters, as Figure 25 and Figure 26 show. When the side edge of the milling cutter 8 is used to mill the side surface of the workpiece 7, the vibration directions of the tool shank and the tool excited are divided into the cutting speed direction and the radial cutting depth direction, the vibration frequency is 5000 Hz, the amplitude in the cutting speed direction is 12 μm, and the phase difference is 0°; when the milling cutter 8 is used to plunge mill the fillet, the vibration direction of the tool excited is along the axial direction, the vibration frequency is 5000 Hz, the amplitude in the axial direction is 12 μm, and the phase difference is 0°.

[0091] S2: Set the cutting fluid pressure to 250 bar, turn on the high-pressure cutting fluid supply, and spray it towards the flank face separation area of chatter cutting.

[0092] S3: Install the milling chatter tool shank on the corresponding machine tool, turn on the machine tool, and perform chatter cutting.

[0093] Example 3: Chatter Grinding of GH4169 Superalloy

[0094] S1: The workpiece 7 is fixed on a grinding machine. Select cutting parameters (cutting linear speed of the tool is 50 m / min, radial depth of cut is 0.1 mm, axial depth of cut is 0.5 mm, feed rate is 0.5 mm / r). Design and manufacture a grinding chatter tool shank that matches the selected cutting parameters, such as Figure 27 The vibration directions excited by the grinding head 9 are divided into the tangential direction and the radial direction of the grinding wheel. The vibration frequency is 5000 Hz, the amplitude in the tangential direction is 12 μm, and the phase difference is 0°.

[0095] S2: Set the cutting fluid pressure to 250 bar, turn on the high-pressure cutting fluid supply, and spray it onto the flank separation area of the chatter cutting.

[0096] S3: Install the grinding chatter tool shank on the corresponding machine tool, turn on the machine tool, and perform chatter cutting.

[0097] Example 4: Chatter drilling of GH4169 superalloy

[0098] S1: The workpiece 7 is fixed on a drilling machine. Select cutting parameters (cutting linear speed of the tool is 50 m / min, feed rate is 0.2 mm / r). Design and manufacture a drilling chatter tool shank that matches the selected cutting parameters, such as Figure 28 , The vibration direction excited by the drill bit 10 is unique and along the axial direction. The vibration frequency is 5000 Hz, and the amplitude in the cutting speed direction is 12 μm.

[0099] S2: Set the cutting fluid pressure to 250 bar, turn on the high-pressure cutting fluid supply, and spray it onto the flank separation area of the chatter cutting.

[0100] S3: Install the drilling chatter tool shank on the corresponding machine tool, turn on the machine tool, and perform chatter cutting.

[0101] Example 5: Chatter reaming of GH4169 superalloy

[0102] S1: The workpiece 7 is fixed on a drilling machine. Select cutting parameters (cutting linear speed of the tool is 50 m / min, feed rate is 0.1 mm / r, depth of cut is 0.2 mm). Design and manufacture a reaming chatter tool shank that matches the selected cutting parameters, such as Figure 29 , The vibration direction excited by the reamer bar 11 is along the axial direction. The vibration frequency is 5000 Hz, and the amplitude in the cutting speed direction is 12 μm.

[0103] S2: Set the cutting fluid pressure to 250 bar, turn on the high-pressure cutting fluid supply, and spray it onto the flank separation area of the chatter cutting.

[0104] S3: Install the reaming chatter tool shank on the corresponding machine tool, turn on the machine tool, and perform chatter cutting.

[0105] Example 6: Chatter countersinking of GH4169 superalloy

[0106] S1: The workpiece 7 is fixed on the countersinking machine. Select the cutting parameters (the cutting linear speed of the tool is 50 m / min, and the feed rate is 0.1 mm / r). Design and manufacture a countersinking chatter tool bar that matches the selected cutting parameters. For example, Figure 30 , the vibration direction excited by the countersinking drill 12 is along the axial direction, the vibration frequency is 5000 Hz, and the amplitude in the cutting speed direction is 12 μm.

[0107] S2: Set the cutting fluid pressure to 250 bar, turn on the high-pressure cutting fluid supply, and spray it towards the flank separation area of the chatter cutting.

[0108] S3: Install the countersinking chatter tool bar on the corresponding machine tool, turn on the machine tool, and perform chatter cutting.

[0109] In the present invention, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. An efficient flutter cutting method for difficult-to-cut materials, It is characterized in that Includes the following: Install the chatter tool bar on the machine tool, turn on the machine tool, and use the cutting energy of the tool system to generate self-excited chatter to perform chatter cutting; During the chatter cutting process, the chatter tool bar is excited to produce a stable vibration, and the tool forms a ratchet-shaped motion trajectory, which includes a process in which the tool squeezes the workpiece surface and the tool separates from the workpiece surface, forming a ratchet-shaped surface morphology on the workpiece surface; During the separation process between the tool and the workpiece surface, the cutting fluid enters the separation cutting zone for cooling and lubrication to reduce the cutting temperature; The process within one vibration cycle of the ratchet-shaped motion trajectory includes: the cutting depth gradually increases, the dynamic back angle continuously decreases until a negative back angle appears, the back tool face continuously squeezes the workpiece surface, the cutting force increases, and the cutting heat accumulates; the tool back angle gradually increases, the cutting depth first increases and then decreases, the cutting force first increases and then decreases, the contact area between the back tool face and the workpiece first increases and then rapidly decreases, the tool back tool face gradually separates from the workpiece surface, the cutting fluid is sprayed from the back tool face of the blade into the separation cutting area, and the cutting temperature rapidly decreases; The vibrating tool bar is designed and manufactured according to the selected processing materials and cutting parameters to ensure that the vibration parameters of the vibrating tool bar are within a reasonable vibration parameter range; the processing materials include aluminum / magnesium / copper alloys, stainless steel, titanium alloys, high-temperature alloys, high-strength steels and composite materials; the cutting parameters include cutting line speed, cutting depth and feed rate; the vibration parameters include the main amplitude and main frequency in the main vibration direction of the vibrating vibration; the reasonable vibration parameter range is related to the workpiece material, tool material and cutting amount, and is based on extending the tool life compared to ordinary cutting.

2. The high-efficiency chatter cutting method for difficult-to-cut materials according to claim 1, Features: The vibration tool bar needs to have its rigidity weakened, and the direction of the rigidity weakening is perpendicular to the direction of the machining surface or along the direction of the rotary cutting speed. During the cutting process, the dynamic change of the cutting force stimulates the vibration tool bar to vibrate along the direction of weak rigidity. At the same time, the rigidity cannot be too weak, so as to extend the tool life compared to ordinary cutting.

3. The high-efficiency chatter cutting method for difficult-to-cut materials according to claim 2, Features: The method of stiffness control includes changing the tool bar material and selecting materials with different elastic moduli as the tool bar material according to needs.

4. The high-efficiency chatter cutting method for difficult-to-cut materials according to claim 1, Features: The ratchet-shaped surface topography is generated by vibration in one or more directions, and the trajectory equation of the relative motion between the tool and the workpiece is as follows: X=A2sin(ωt) Y=A1sin(ωt+φ)+vt Where X is the displacement perpendicular to the workpiece surface, Y is the displacement along the cutting speed direction, A1 is the amplitude along the cutting speed direction, A2 is the amplitude perpendicular to the workpiece surface, ω is the chatter frequency of the tool in the cutting speed direction, φ is the phase difference between the vibrations in the two directions, t is the time, v is the cutting linear velocity, and the trajectory of the relative motion between the tool and the workpiece can be obtained with Y as the horizontal coordinate and X as the vertical coordinate.

5. The high-efficiency chatter cutting method for difficult-to-cut materials according to claim 1, It is characterized in that: A triaxial acceleration sensor is attached to the vibrating part of the chatter tool bar to measure the amplitude, frequency and phase difference in each direction, determine the vibration trajectory of the chatter tool bar and the tool, the main chatter frequency of the chatter tool bar is close to the natural frequency in the main vibration direction, perform natural modal analysis and design on the chatter tool bar, and regulate the chatter frequency.

6. The high-efficiency chatter cutting method for difficult-to-machine materials according to claim 1, It is characterized in that: The chatter cutting includes chatter turning, chatter milling, chatter grinding, chatter drilling, chatter reaming and chatter counterboring.

7. The high-efficiency chatter cutting method for difficult-to-machine materials according to claim 1, It is characterized in that: The cutting fluid is oil-based cutting fluid, oil-based cutting mist, water-based cutting fluid, water-based cutting mist or liquid nitrogen, and the pressure of the cutting fluid is determined according to the machine tool conditions and process effect requirements.

8. The high-efficiency chatter cutting method for difficult-to-machine materials according to claim 1, It is characterized in that: The machine tool includes a lathe, a milling machine, a drilling machine, a grinding machine and a machining center capable of performing cutting processing technologies.

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